Canada has seen a rise in negative advertisements during our election seasons - I remember reading an article about how our election process is being influenced by the US elections. I anticipate that as yours increase, so to shall ours.
There is a line here though. Remember when Kim Campbell ran ads showing Jean Chretien's face, a deformity he was born with. It back fired and the Tories were reduced to two seats from 264. They tread lightly here and the negative ads are usually third party, usually unions attacking the government. In Canada third party ads cannot endorse a particular candidate, only "discuss" issues, of the vehemence of the attacks are much less.
Too bad the Republicans didn't. Seriously, the parallels between Kerry and Romney are really kinda remarkable.
Well, other than a distortion of the user name and what it stands for, it does usually produce a loathing - the created fear in demonizing a candidate is deep and very personal.
The US is becoming more and more about personalities, or rather the created perception of the personality. You are correct, Kerry tried it with Bush and got his clock cleaned badly.
I do not see where Romney has done anything like that. At least what we get here, through the filter of a border and a democrat state - Washington is that the Republicans have hammered away at the economy while the Democrat ads talk about Romney, Romney, Romney,
But then Washington is not exactly a "battleground state"